A technique for cutting out a plurality of dies (semiconductor chips) from a sheet of wafer having semiconductor elements on it by utilizing a dicing saw or similar equipment is known to the public. Both FIG. 14A and FIG. 14B show views of processes for cutting out the dies from the wafer (when "full cutting method" is carried out). At first, a plastic film 4 coated with adhesive on a surface is attached under the wafer 2 as shown in FIG. 14A. Then, the wafer 2 is cut completely with the dicing saw 6. Thus, a plurality of dies 8 can be cut out from the sheet of wafer 2 (see FIG. 15).
However, the cutting method described above has the following problems to be resolved. A part of the dies 8 might be chipped by the dicing saw 6 when the cutting method is carried out. Especially, corners 8a of the dies 8 located at vicinity of intersection points 14 where lines for scribing (hereinafter referred to as scribing lines) intersect are chipped often as shown in FIG. 15. The scribing lines consist of longitudinal lines 10 extended to a longitudinal direction and transverse lines 12 extended to a transverse direction.
As shown in FIG. 16, water resistance and other advantageous features of the dies 8 are destroyed by damaging a protection layer 16 such as crack or similar phenomena caused by chips caused at the corners 8a when upper part of the dies 8 are covered with the protection layer 16 made of silicon nitride layer (SiN) or a material having similar chemical formula.
The problems described earlier clearly appear when spaces being formed between dies 8 located adjacently are made under a narrower width in order to cut out as many as dies 8 possible from the wafer 2. In other words, these problems appear when margins of the scribing lines are narrower than usual.